Surface Tension of Water by Capillary Rise and Effect of Detergents NEET Questions

Surface Tension of Water by Capillary Rise and Effect of Detergents

Surface Tension of Water by Capillary Rise and Effect of Detergents MCQ Questions

13.
For mercury in a glass tube, the angle of contact is approximately:
A.
45°
B.
0°
C.
140° (mercury does not wet glass)
D.
90°
ANSWER :
C. 140° (mercury does not wet glass)
14.
If the angle of contact θ < 90°, the meniscus is:
A.
Flat
B.
Spherical bead
C.
Convex (dome-shaped)
D.
Concave (cup-shaped, dipping in the middle)
ANSWER :
D. Concave (cup-shaped, dipping in the middle)
15.
If the angle of contact θ > 90°, the meniscus is:
A.
Convex (dome-shaped)
B.
Concave
C.
Inverted
D.
Flat
ANSWER :
A. Convex (dome-shaped)
16.
If the angle of contact is exactly 90°, the:
A.
Liquid evaporates
B.
Meniscus is flat and there is no capillary rise or depression
C.
Liquid is depressed
D.
Liquid rises to maximum
ANSWER :
B. Meniscus is flat and there is no capillary rise or depression
17.
Pure water rises in a clean glass capillary because:
A.
Cohesion is greater than adhesion
B.
Gravity is weak
C.
Glass is hot
D.
Adhesion (water-glass) is greater than cohesion (water-water); θ < 90°
ANSWER :
D. Adhesion (water-glass) is greater than cohesion (water-water); θ < 90°
18.
Mercury depresses in a glass capillary because:
A.
Glass is hot
B.
Mercury is metallic
C.
Cohesion (Hg-Hg) is greater than adhesion (Hg-glass); θ > 90°
D.
Mercury is denser than glass
ANSWER :
C. Cohesion (Hg-Hg) is greater than adhesion (Hg-glass); θ > 90°